The Trinji (pronounced "trin-ZHEE" by its inhabitants) System is vast and extreme. The blue sun bombards its inner planets with intense radiation, while its outer planets are so distant that they receive little or virtually no heat. A vast asteroid belt separates the inner two planets from the outer two, although the field is not a significant hinderance to space faring navigation. A handful of moons can also be found in the Trinji System: one medium-sized satellite (called Amuliadarvin) around Deladarvin and four tiny moons (Kao, Dabi, Awulya, and Mull, named after four extinct predatory species from Deladarvin) around the gas giant Kepelya.
When the long-vanished alien civilization passed through the Trinji System ages ago, they thought that only the planet which would one day be called Deladarvin showed any promise for supporting sentient life. They were wrong. In the eons between the aliens' exploration of Deladarvin and the evolution of the sentient Darvin species, asteroids struck the planet and expelled portions of it into space. Frozen specimens of the microbial life from Deladarvin were thus carried to the planet that would in the future be known as Ul-Vilyeth. Under the intense radiation of the Trinji sun, the microbial life transplanted to Ul-Vilyeth mutated over millions of years into a wildly new species.
Only in the past century have the two sentient species of the Trinji System had contact with each other, and the interaction has not been altogether equal. Darvin society is vastly more technologically advanced than Ulvi society. It is also a much more unified culture with a single species-wide language (hence why all celestial bodies are known by their Darvin names). What sorts of changes interaction with new species will bring to Darvin-Ulvi relations remains to be seen.